A bstract We study the relativistic limit of the worldsheet S-matrix of AdS 3 × S 3 × S 3 × S 1 strings in the presence of mixed Ramond-Ramond (RR) and Neveu-Schwarz-Neveu-Schwarz (NS-NS) flux and complete the S-matrix bootstrap including the dressing factors for fundamental particles and bound states. Our results agree with the relativistic limit of the recent proposal arXiv:2512.07721.
Cattaneo et al. (Wed,) studied this question.